Evolution can be described as the change in frequencies of a over time.

Explanation:

In population genetics, the term evolution is defined as a change in the frequency of an allele in a population. ... The allele frequency within a given population can change depending on environmental factors; therefore, certain alleles become more widespread than others during the process of natural selection.

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.